Is the neuron adequately comprehended?
No, here is why. No approach can simulate the mind with 100% accuracy. a major notion that AI theorist refuse to note is that you cant take an orange and by virtue of technology turn it into an apple lets apply the same logic here. 

neurons are temporary things in our brains, daily we are trimming our brains and growing our brains, in order to "Engineer" a human Brain a probability whatever or not that neuron would die or not would have to be present. But that probability is flawed as well because, Nature is not math. In this case we are trying to apply something to Math that is unpredictable. Math is something we have used to try to rationalize the way nature works but it out right fails. If nature is completely math then predicting a hurricane would be easy. 

So to answer your question, no because a Neuron is more then a light switch, it is not mathematical in nature. their is no universality in everyone. plus their is more variables that you would have to account for that are way beyond a simple decision and a simple mathematical formula.